The Trouble with Topping Trees
Trees are remarkably resilient organisms.
Because they compartmentalize, or seal off, their wounds, skilled arborists can prune trees to improve their health, alter their structure or improve fruit and flower production. As long as the arborist does not remove too much of the canopy, and he or she places cuts in the right locations, the tree is unlikely to suffer.
However, improper pruning practices can weaken even the healthiest specimens. In especially tragic cases, improper pruning can lead to the tree's premature demise. Such is often the case whenever trees suffer a particularly horrible pruning practice called “topping."
What Is Topping?
Topping is the process of pruning a tree in a straight horizontal plane, much as a landscaper may trim a hedge. It results in an odd-looking (some might even say ugly) tree, that contains numerous stubby branches. You may see topped trees anywhere unskilled tree professionals wield saws, but they are especially common under utility lines, as the trees must not be allowed to contact the wires.
Problems Caused By Topping Trees
Topped trees certainly compromise the aesthetics of the tree and the surrounding area, but the technique causes a variety of other problems for the tree as well.
• Topping removes too much of the tree’s canopy at one time. Generally, arborists do not remove more than one-fourth of a tree’s canopy at one time. When trees lose significant amounts of their canopies, they struggle to produce enough food for themselves.
• Drastic alterations of a tree’s canopy may expose formerly shaded areas to the sun. It can lead to sunscald, also known as southwest injury, which is particularly harmful for tree species with thin bark. Additionally, as the tree’s canopy may have also provided shade to other nearby trees and plants, these neighboring plants may suffer from sunscald as well.
• When trees are topped, the branches are seldom pruned correctly. Instead of making cuts close to branch junctions, where a tree can quickly compartmentalize the wound to protect the stub from insects and disease, those topping trees often place their cuts in the middle of branch segments, where trees are unable to seal off the wound quickly or efficiently. This leaves the stubs vulnerable to infection and infestation, which may ultimately spread through the rest of the tree.
• In response to the drastic reduction in canopy cover, trees often respond to topping by producing an abundance of branches. These branches, which are often called water sprouts, attach weakly to the tree. Over time, these branches will grow large and ultimately fall, placing people and property at risk.
The primary reason trees are subjected to topping is that they have grown too tall for the space in which they were planted. While skilled arborists can safely reduce the height of some trees, the best solution is to plant suitable species for the location. By planting trees that reach only modest heights in such places, you can alleviate the need for such drastic and destructive pruning practices.
Topping is illegal in the city of San Francisco. Do your part to end the practice by reporting trees that have been topped.
If your trees are rapidly outgrowing their surroundings, give Arborist Now a call. We offer a full line of residential and commercial tree services in Millbrae, San Francisco and the rest of the Bay Area. Our skilled arborists can examine the tree and recommend a suitable approach for resolving the problem. Alternatively, if you are interested in planting new trees, our arborists can help you determine which species will stay small enough for the spot available.